Flu activity on the rise; CDC urges ongoing vaccination
As of early November, only about 2 out of 5 people in the United States reported having gotten this season's flu vaccine, yet flu vaccine offered substantial benefit last season by preventing an estimated 5 million flu illnesses and 71,000 flu hospitalizations. CDC is releasing this information during the 11th National Influenza Vaccination Week (NIVW), an event to encourage ongoing flu vaccination into the holidays and beyond.
"We are glad to see that people are making the decision to protect themselves and their families from flu, but coverage is still low and we urge people to get vaccinated if they haven't yet," said Nancy Messonnier, M.D., director of CDC's National Center for Immunization and Respiratory Diseases. "We have a tool that is proven to prevent flu illness and hospitalization but millions of people are not taking advantage of it. Too many people are unprotected."
Flu vaccine coverage estimates based on survey data collected through early November 2016 show vaccination levels similar to this time last season. Forty percent of people overall reported having received a flu vaccine, including 37 percent of children ages 6 months to 17 years and 41 percent of adults ages 18 years and older.
Although flu vaccination estimates among adults and children are similar to early estimates from last season for all age groups, CDC is looking carefully at vaccination rates for children and for adults ages 50 years and older.
"We are urging parents to make sure their children get a flu shot this season, as the nasal-spray vaccine is not recommended for the 2016-2017 flu season. An annual flu vaccine is very important protection for children," said Joe Bresee, M.D., a pediatrician and chief of the Epidemiology and Prevention Branch of CDC's Influenza Division.
Concern about vaccination among older adults is prompted by detection of a three percentage point decrease in vaccine coverage among people 50 years and older in final vaccine coverage estimates for 2015-16 compared to 2014-15. "It's too soon to say whether vaccination in people 50 and older will rebound this season. We certainly hope it will," Messonnier said. "About a third of people ages 50 to 64 have medical conditions that put them at high risk of serious flu complications; and we know that declining immune function puts people 65 and older at high risk. While flu vaccination is recommended for everyone 6 months and older, it's especially important that people in high-risk groups get vaccinated."
CDC also surveyed pregnant women and health care workers regarding flu vaccination:
*While early estimates show vaccination among pregnant women (47 percent) is six percentage points higher than early estimates last season, more than half of pregnant women remain unvaccinated.
*Vaccination among health care providers (69 percent) is about the same as it was at this time last season.
*Last season, coverage among health care personnel working in long-term care facilities increased five percentage points (to 69 percent), but was still the lowest among all health care provider groups. The early coverage estimate for those providers this season (55 percent) is still the lowest among all health care providers.
"It is really important that health care workers get vaccinated and especially important that we continue to make progress vaccinating health care workers who work in long-term care facilities. Many of the most frail and vulnerable people live in these facilities and we know that vaccinating their caregivers helps protect them," said Messonnier.
Reducing the burden of disease
Flu is unpredictable and every season is different. CDC reports that H3N2 viruses are predominant so far. H3N2-predominant seasons often are more severe, especially for young children and people 65 and older. So far, most influenza viruses collected since October 1 remain similar to the vaccine viruses recommended for vaccine production.
CDC also is releasing a report on the impact of influenza vaccination during 2015-16. Flu vaccination last season is estimated to have reduced the amount of flu illnesses and hospitalizations that would have occurred in an unvaccinated population by 19 percent. The report illustrates not only the benefits of influenza vaccination, but also the burden of flu and missed opportunities to prevent illness through vaccination. There were an estimated 25 million flu illnesses and 310,000 flu-associated hospitalizations in the United States last season - but if vaccination rates had been 5 percentage points higher, another 500,000 flu illnesses and 6,000 flu-related hospitalizations could have been prevented. Or, if vaccination rates had reached the Healthy People 2020 goal of 70 percent across all age groups, an additional 2.4 million flu illnesses and 19,000 flu hospitalizations would have been prevented.
The report also updates estimates on flu hospitalizations and deaths in the United States since 2010. CDC estimates that flu-related hospitalizations ranged from 140,000 to 710,000. The previous citation of "more than 200,000" annual flu-related hospitalizations was based on data from 1979 to 2001. Influenza-associated deaths in the United States are estimated to have ranged from 12,000 to 56,000 since 2010. The previously cited range of "3,000 to 49,000" was based on respiratory and circulatory deaths reported from 1976 to 2007.
While vaccination is the first and best way to prevent flu, CDC also recommends influenza antiviral drugs as a second tool to fight flu. Antiviral drugs are not a substitute for vaccination. Treatment with antiviral drugs is recommended for people at high risk of serious flu complications or people who are very sick with flu.
National Influenza Vaccination Week was established in 2005 to highlight the importance of continuing flu vaccination throughout the flu season. Past vaccine coverage data has shown that flu vaccination activity drops after November. However, influenza activity has peaked between December and February about 75 percent of the time in the past 30 years, and significant flu activity can occur as late as May, meaning that vaccination after November would still offer substantial protection during most seasons.